When I was a kid, I shared a room with my baby brother and routinely slept through his nighttime crying. In college, I was profiled by the campus newspaper for my impressive napping skills. To say I am a heavy sleeper is a bit of an understatement. 
That all went out the window the second I became a mother, though. Even in the post-labor exhaustion of the first night alone in our hospital room, I woke in a panic at the slightest sound from our son’s bassinet. The immediate physical and emotional connection I felt with him flabbergasted me. I’d never experienced anything like it before. Now I know there’s a reason for my newfound sleeplessness, one that can’t be blamed solely on pesky nighttime feedings. 
A recent study by Elseline Hoekzema and colleagues, published in the journal Nature Neuroscience, showed that significant, long-lasting changes occur in a woman’s brain during pregnancy.
Baby, you’re always on my mind.
Because the effects of pregnancy on the human brain have not been studied in-depth, Hoekzema set out to discover what actually happens inside a woman’s brain during pregnancy. According to the study’s abstract, Hoekzema’s research showed “that pregnancy renders substantial changes in brain structure, primarily reductions in gray matter (GM) volume in regions subserving social cognition. …Furthermore, the GM volume changes of pregnancy predicted measures of postpartum maternal attachment, suggestive of an adaptive process serving the transition into motherhood.” 
Women experience a significant reduction in gray matter during their teenage years as well, which scientists attribute to a surge in sex hormones during adolescence. According to the study, “In adolescence, these GM reductions are … generally regarded as an essential process of fine-tuning connections into functional networks and is thought to represent a refinement and specialization of brain circuitry, which is critical for healthy cognitive, emotional and social development.” As a result of the study, scientists concluded that increased hormones during pregnancy cause women to experience a similar reduction in gray matter volume in the association areas of the cerebral cortex, which are responsible for forming social attachments. 
Dr. Jaime Knopman, cofounder of Truly, MD and Director of Fertility Preservation at Colorado Center for Reproductive Medicine New York, tells HealthyWay, “These changes appear to persist for up to two years post-delivery. Although it is not totally clear why these changes occur, it is thought that these changes help [women] respond to their babies and adapt to motherhood.” As Knopman notes, these changes can last well into the postpartum period. While Hoekzema only studied postpartum women for two years, the effects of pregnancy on a woman’s brain could actually last much longer. In an animal study, rats experienced permanent changes in the brain long after pregnancy. 
Hoekzema’s report also explains that a loss of gray matter does not mean loss of brain function. In fact, the greater the gray matter reduction, the stronger a woman bonded with her baby postpartum. This effect was not observed in new fathers or in either women or men who recently adopted new babies.
Forget something? Blame it on baby brain.
While I was pregnant, I was notoriously forgetful. I’d get to the grocery store and realize I’d left my purse at home. This forgetfulness has only gotten worse since my son was born. Just last week I brewed the morning coffee, only to find hot coffee pooling on the floor and the pot sitting where I’d left it by the sink. 
Knopman explains, “While pregnancy has its most visible impact on your belly, it can have a significant impact on all parts of your body—including your brain. Yes, pregnancy brain is not a joke! …Pregnancy is dominated by hormones—estrogen and progesterone levels soar during this period. The surge in these hormones [has] been correlated with the change in structural and organizational changes in the brain.” Dr. Angela Jones, Astroglide’s resident sexual health advisor, agrees. “I see [pregnancy brain] on a pretty daily basis, expectant moms not being able to remember the questions they were going to ask me at a particular visit: ‘Sorry, it’s pregnancy brain.’ I think it is a great start in recognizing just how dynamic pregnancy is and all of the potential systems that are affected. With all the hormonal fluctuations [and] surges characteristic of pregnancy, it’s nice to have some semblance of an explanation as to what exactly is going on and why we experience ‘pregnancy brain.’” 
Knopman continues, “While theoretically a change in gray matter could contribute to the brain fog frequently experienced during and after pregnancy, scientists have long thought that the mental changes experience are due to a rise in hormone (estrogen and progesterone) and their impact on brain neuronal circuits.” The study didn’t definitively correlate the brain fog pregnant women commonly experience with reduced gray matter in the brain, but it didn’t rule out the possibility that the two are connected, either. Hoekzema concluded that GM reduction in certain parts of a woman’s brain helps promote bonding between mother and child. Similarly, Knopman says that the brain fog women experience postpartum “is a way to forget all else and focus on your baby—simply stated, an evolutionary response to think about nothing but your newborn.”
Help your evolutionary biology sync with your modern mama life.
If you’re walking around in a bit of a haze during the last trimester, there are a few things you can do to sharpen your memory. During those last weeks of pregnancy, I wanted nothing more than to lie on the couch and eat Dairy Queen Blizzards that my husband dutifully walked down the block to get. The absolute last thing I wanted to do was walk with him to get my frozen treat. However, a nightly walk could have done more than satisfy my sweet tooth. According to my OB-GYN’s office, exercise can actually help sharpen your memory. Unless you’re Serena Williams, most doctors recommend pregnant women get 30 minutes of light cardio, like walking or swimming, daily. 
My doctor also suggested taking naps throughout the day to reduce the amount of brain fog I experienced. Considering I woke up to use the restroom approximately a dozen times a night, coupled with the fact that it is nearly impossible to find a comfortable sleeping position when pregnant, this nap prescription was not hard to follow. Plus, now that my son is born, naps are a thing of the past. My advice? Nap away, and don’t feel guilty about it!
Can you avoid the baby blues?
Postpartum mood disorders such as depression affect up to 1.3 million women annually. Jones says, “It’s completely normal for any new mom to experience what is called postpartum blues. Postpartum blues is characterized by feeling overwhelmed, anxiety, periods of tearfulness, mood swings, etc. and usually has its onset two to three days post delivery and can last up to two weeks.” 
I, for one, experienced the baby blues when we brought my son home from the hospital. Everything, and I do mean everything, made me weepy. Commercials, a certain song on the radio, even an episode of The Golden Girls reduced me to tears. The self-care information I was given at hospital checkout said this is standard for most women as hormone levels fluctuate and their bodies return to “normalcy” following delivery. However, Jones explains that baby blues that last longer than two weeks aren’t normal. 
“Postpartum depression is [often] overlooked and attributed to postpartum blues. The difference is, postpartum blues typically resolves … if more than two weeks have passed and you are still feeling sad, overwhelmed, having difficulty bonding with baby, crying all the time, having difficulty sleeping, not eating, feeling depressed, withdrawn, not enjoying activities that routinely bring you pleasure, feeling inadequate … the list goes on and on, you should see your OB-GYN immediately.” Hoekzema’s study may be able to predict if a woman is more likely to develop postpartum depression. Researchers’ findings “indicated that the GM volume changes of pregnancy significantly predicted the quality of mother-to-infant attachment and the absence of hostility.” 
The study goes on: “To further investigate the possibility of an adaptive restructuring to facilitate aspects of motherhood, we examined the observed brain changes in relation to indices of maternal caregiving. Multivariate regression analyses using the three dimensions of the Maternal Postnatal Attachment Scale demonstrated that the GM volume changes of pregnancy significantly predicted quality of mother-to-infant attachment and the absence of hostility toward her newborn in the postpartum period. “In addition, a substantial overlap was observed between the GM tissue undergoing volume reductions across pregnancy and the brain areas of strongest neural responsivity to pictures of the women’s babies in a postpartum MRI session. Taken together, our findings provide preliminary support for an adaptive refinement of social brain structures that benefits the transition into motherhood.” 
In layman’s terms, the study suggests that women who do not experience significant reduction in gray matter volume experience greater difficulty forming attachments to their babies, which may increase the likelihood that they will experience postpartum mood disorders. “While this study doesn’t come close to being able to draw definitive conclusions such as if changes noted are lasting, or treatment options for possible links to affected areas of the brain, specifically postpartum depression … I think it is a great start in recognizing just how dynamic pregnancy is,” says Jones. 
With just under 4 million babies born each year in the United States, the research Hoekzema and her colleagues are conducting is just the beginning of what scientists and doctors can learn about pregnancy’s effect on a woman’s body, long after labor and delivery.
